<template>
  <div class='xtx-carousel' @mouseenter="stop()" @mouseleave="start()">
  <!--轮播图图片容器-->
    <ul class="carousel-body">
    <!--fade 显示的图片加上-->
      <li class="carousel-item" v-for="(item,i) in sliders" :key="i" :class="{fade:index===i}">
        <!-- 图片 -->
        <RouterLink v-if="item.hrefUrl" :to="item.hrefUrl">
          <img :src="item.imgUrl" alt="">
        </RouterLink>
        <!-- 商品列表 -->
        <div v-else class="slider">
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img :src="goods.picture" alt="">
            <p class="name ellipsis">{{goods.name}}</p>
            <p class="price">&yen;{{goods.price}}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
  <!--上一张-->
    <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev"><i class="iconfont icon-angle-left"></i></a>
  <!--下一张-->
    <a @click="toggle(1)" href="javascript:;" class="carousel-btn next"><i class="iconfont icon-angle-right"></i></a>
  <!--指示器-->
    <div class="carousel-indicator">
    <!--active 激活点-->
      <span @click="index=i" v-for="(item,i) in sliders" :key="i" :class="{active:index===i}"></span>
    </div>
  </div>
</template>

<script>
import {onUnmounted, ref,watch} from 'vue'
export default {
  name: 'XtxCarousel',
  props:{
      //轮播图数据
      sliders:{
          type:Array,
          default:()=>[]
      },
      //是否自动轮播
      autoPlay:{
          type:Boolean,
          default:false
      },
      //间隔时长
      duration:{
          type:Number,
          default:3000
      }
  },
  setup(props){
      //控制显示图片的索引
      const index =ref(0)

        //1.自动轮播图的逻辑
        let timer = null
        const autoPlayFn=()=>{
            //防止计时器重复添加
            clearInterval(timer)
            //自动播放，每隔一段时间切换索引
            timer=setInterval(()=>{
                index.value++
                if(index.value>=props.sliders.length){
                    index.value=0
                }
            },props.duration)
        }
        //需要监听sliders数据变化,判断如果有数据且autoPlay是true
        watch(()=>props.sliders,(newVal)=>{
            if(newVal.length && props.autoPlay){
                autoPlayFn()
            }
        },{immediate:true})

        //2.鼠标进入暂停，离开开启自动播放（有开启条件）
        const stop=()=>{
            if(timer)clearInterval(timer)
        }
        const start =()=>{
            if(props.sliders.length&&props.autoPlay){
                autoPlayFn()
            }
        }
        //3.点击上一张下一张以及跑马灯，实现切换
        const toggle=(step)=>{
            //将要改变的索引
            const newIndex=index.value+step
            //超出的情况，太大了
            if(newIndex > (props.sliders.length-1)){
                index.value=0
                return
            }
            //超出的情况，太小了
            if(newIndex < 0){
                index.value=props.sliders.length-1
                return
            }
            //正常
            index.value=newIndex
        }
        //4.组件卸载，清楚定时器
        onUnmounted(()=>{
            clearInterval(timer)
        })

      return {index,stop,start,toggle}
  }
}
</script>
<style scoped lang="less">
.xtx-carousel{
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel{
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0,0,0,0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background:  #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0,0,0,.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev{
        left: 20px;
      }
      &.next{
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
// 轮播商品
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px!important;
      height: 230px!important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>
